Unexpected sex-ratios in families of language/learning-impaired children.

There is a well-documented propensity of males affected with developmental language/learning impairment. Results from this study demonstrate, unexpectedly, that this sex-ratio difference of males to females with developmental language/learning disorders was found to occur significantly only in families with a language/learning-impaired mother. In addition, a remarkably aberrant offspring sex-ratio was found in families of language/learning-impaired children who had an affected mother, but not father. Mothers who were developmentally language/learning-impaired had three times as many sons as daughters, and five times as many language/learning-impaired sons as daughters. Genetic and hormonal influences that might affect both sex-ratio and neuroanatomical development and disorders are discussed.